v3.25.4
Note 8 Transfer between levels (Details) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Level 1 Of Fair Value Hierarchy [Member] | Financial liabilities at fair value through profit or loss that meet definition of held for trading, category [member]      
Level transfers [Line Items]      
Transfers out of Level 1 into Level 2 of fair value hierarchy, liabilities held at end of reporting period € 19 € 107 € 596
Transfers into Level 3 of fair value hierarchy, liabilities 0 0 3
Level 1 Of Fair Value Hierarchy [Member] | Financial liabilities at fair value through profit or loss, mandatorily measured at fair value, category      
Level transfers [Line Items]      
Transfers out of Level 1 into Level 2 of fair value hierarchy, liabilities held at end of reporting period 0 0 0
Transfers into Level 3 of fair value hierarchy, liabilities 0 0 0
Level 1 Of Fair Value Hierarchy [Member] | Derivatives [member]      
Level transfers [Line Items]      
Transfers out of Level 1 into Level 2 of fair value hierarchy, liabilities held at end of reporting period 0 0 0
Transfers into Level 3 of fair value hierarchy, liabilities 0 0 0
Level 1 Of Fair Value Hierarchy [Member] | Total transferred financial liabilities [Member]      
Level transfers [Line Items]      
Transfers out of Level 1 into Level 2 of fair value hierarchy, liabilities held at end of reporting period 19 107 596
Transfers into Level 3 of fair value hierarchy, liabilities 0 0 3
Level 1 Of Fair Value Hierarchy [Member] | Financial assets at fair value through profit or loss, classified as held for trading, category [member]      
Level transfers [Line Items]      
Transfers out of Level 1 into Level 2 of fair value hierarchy, assets held at end of reporting period 181 115 887
Transfers into Level 3 of fair value hierarchy, assets 0 0 34
Level 1 Of Fair Value Hierarchy [Member] | Non trading financial assets mandatorily at fair value through profit or loss [Member]      
Level transfers [Line Items]      
Transfers out of Level 1 into Level 2 of fair value hierarchy, assets held at end of reporting period 5,150 68 1
Transfers into Level 3 of fair value hierarchy, assets 30 14 135
Level 1 Of Fair Value Hierarchy [Member] | Financial assets at fair value through profit or loss, category [member]      
Level transfers [Line Items]      
Transfers out of Level 1 into Level 2 of fair value hierarchy, assets held at end of reporting period 0 0 0
Transfers into Level 3 of fair value hierarchy, assets 0 0 0
Level 1 Of Fair Value Hierarchy [Member] | Financial assets at fair value through other comprehensive income, category [member]      
Level transfers [Line Items]      
Transfers out of Level 1 into Level 2 of fair value hierarchy, assets held at end of reporting period 251 1,425 1,191
Transfers into Level 3 of fair value hierarchy, assets 36 17 21
Level 1 Of Fair Value Hierarchy [Member] | Derivatives [member]      
Level transfers [Line Items]      
Transfers out of Level 1 into Level 2 of fair value hierarchy, assets held at end of reporting period 0 0 0
Transfers into Level 3 of fair value hierarchy, assets 0 0 0
Level 1 Of Fair Value Hierarchy [Member] | Total transferred financial assets [Member]      
Level transfers [Line Items]      
Transfers out of Level 1 into Level 2 of fair value hierarchy, assets held at end of reporting period 5,582 1,608 2,079
Transfers into Level 3 of fair value hierarchy, assets 66 31 190
Level 2 Of Fair Value Hierarchy [Member] | Financial liabilities at fair value through profit or loss that meet definition of held for trading, category [member]      
Level transfers [Line Items]      
Transfers out of Level 2 into Level 1 of fair value hierarchy, liabilities held at end of reporting period 269 461 36
Transfers out of level 2 into level 3 (144) (45) (177)
Level 2 Of Fair Value Hierarchy [Member] | Financial liabilities at fair value through profit or loss, mandatorily measured at fair value, category      
Level transfers [Line Items]      
Transfers out of Level 2 into Level 1 of fair value hierarchy, liabilities held at end of reporting period 0 0 0
Transfers out of level 2 into level 3 (1,021) (301) (660)
Level 2 Of Fair Value Hierarchy [Member] | Derivatives [member]      
Level transfers [Line Items]      
Transfers out of Level 2 into Level 1 of fair value hierarchy, liabilities held at end of reporting period 0 0 0
Transfers out of level 2 into level 3 0 0 0
Level 2 Of Fair Value Hierarchy [Member] | Total transferred financial liabilities [Member]      
Level transfers [Line Items]      
Transfers out of Level 2 into Level 1 of fair value hierarchy, liabilities held at end of reporting period 269 461 36
Transfers out of level 2 into level 3 877 (346) (837)
Level 2 Of Fair Value Hierarchy [Member] | Financial assets at fair value through profit or loss, classified as held for trading, category [member]      
Level transfers [Line Items]      
Transfers out of Level 2 into Level 1 of fair value hierarchy, assets held at end of reporting period 344 1,238 89
Transfers out of level 2 into level 3 (272) (78) (666)
Level 2 Of Fair Value Hierarchy [Member] | Non trading financial assets mandatorily at fair value through profit or loss [Member]      
Level transfers [Line Items]      
Transfers out of Level 2 into Level 1 of fair value hierarchy, assets held at end of reporting period 9 1 0
Transfers out of level 2 into level 3 0 0 (70)
Level 2 Of Fair Value Hierarchy [Member] | Financial assets at fair value through profit or loss, category [member]      
Level transfers [Line Items]      
Transfers out of Level 2 into Level 1 of fair value hierarchy, assets held at end of reporting period 7 1 0
Transfers out of level 2 into level 3 0 0 0
Level 2 Of Fair Value Hierarchy [Member] | Financial assets at fair value through other comprehensive income, category [member]      
Level transfers [Line Items]      
Transfers out of Level 2 into Level 1 of fair value hierarchy, assets held at end of reporting period 762 1,348 1,296
Transfers out of level 2 into level 3 (43) (12) (205)
Level 2 Of Fair Value Hierarchy [Member] | Derivatives [member]      
Level transfers [Line Items]      
Transfers out of Level 2 into Level 1 of fair value hierarchy, assets held at end of reporting period 0 0 0
Transfers out of level 2 into level 3 0 0 0
Level 2 Of Fair Value Hierarchy [Member] | Total transferred financial assets [Member]      
Level transfers [Line Items]      
Transfers out of Level 2 into Level 1 of fair value hierarchy, assets held at end of reporting period 1,122 2,586 1,385
Transfers out of level 2 into level 3 (315) (90) (941)
Level 3 Of Fair Value Hierarchy [Member] | Financial liabilities at fair value through profit or loss that meet definition of held for trading, category [member]      
Level transfers [Line Items]      
Transfers out of Level 3 of fair value hierarchy, liabilities (3) (11) (1)
Transfers out of level 3 into level 2 of fair value hierarchy liabilities 259 380 372
Level 3 Of Fair Value Hierarchy [Member] | Financial liabilities at fair value through profit or loss, mandatorily measured at fair value, category      
Level transfers [Line Items]      
Transfers out of Level 3 of fair value hierarchy, liabilities (256) 0 0
Transfers out of level 3 into level 2 of fair value hierarchy liabilities 103 121 262
Level 3 Of Fair Value Hierarchy [Member] | Derivatives [member]      
Level transfers [Line Items]      
Transfers out of Level 3 of fair value hierarchy, liabilities 0 0 0
Transfers out of level 3 into level 2 of fair value hierarchy liabilities 0 0 0
Level 3 Of Fair Value Hierarchy [Member] | Total transferred financial liabilities [Member]      
Level transfers [Line Items]      
Transfers out of Level 3 of fair value hierarchy, liabilities (254) (11) (1)
Transfers out of level 3 into level 2 of fair value hierarchy liabilities 362 501 635
Level 3 Of Fair Value Hierarchy [Member] | Financial assets at fair value through profit or loss, classified as held for trading, category [member]      
Level transfers [Line Items]      
Transfers out of Level 3 of fair value hierarchy, assets 30 16 0
Transfers out of level 3 into level 2 of fair value hierarchy assets 200 199 497
Level 3 Of Fair Value Hierarchy [Member] | Non trading financial assets mandatorily at fair value through profit or loss [Member]      
Level transfers [Line Items]      
Transfers out of Level 3 of fair value hierarchy, assets 0 35 0
Transfers out of level 3 into level 2 of fair value hierarchy assets 33 18 0
Level 3 Of Fair Value Hierarchy [Member] | Financial assets at fair value through profit or loss, category [member]      
Level transfers [Line Items]      
Transfers out of Level 3 of fair value hierarchy, assets 0 0 0
Transfers out of level 3 into level 2 of fair value hierarchy assets 0 0 0
Level 3 Of Fair Value Hierarchy [Member] | Financial assets at fair value through other comprehensive income, category [member]      
Level transfers [Line Items]      
Transfers out of Level 3 of fair value hierarchy, assets 0 13 103
Transfers out of level 3 into level 2 of fair value hierarchy assets 105 170 243
Level 3 Of Fair Value Hierarchy [Member] | Derivatives [member]      
Level transfers [Line Items]      
Transfers out of Level 3 of fair value hierarchy, assets 0 0 0
Transfers out of level 3 into level 2 of fair value hierarchy assets 0 0 0
Level 3 Of Fair Value Hierarchy [Member] | Total transferred financial assets [Member]      
Level transfers [Line Items]      
Transfers out of Level 3 of fair value hierarchy, assets 30 64 103
Transfers out of level 3 into level 2 of fair value hierarchy assets € 338 € 387 € 740